Temperatures rise over flu vaccine study

  The debate is heating up over the value of influenza vaccines, as a study suggests the effectiveness may be lower than was previously thought. The study of three years of hospital and general practice data found that influenza vaccine effectiveness was modest – an estimated 39% for hospitalised patients and 50% in general practice […]

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The debate is heating up over the value of influenza vaccines, as a study suggests the effectiveness may be lower than was previously thought.

The study of three years of hospital and general practice data found that influenza vaccine effectiveness was modest – an estimated 39% for hospitalised patients and 50% in general practice patients.

This compares to the 10th edition of the Immunisation Handbook (2013) that stated flu vaccines were 59% effective in preventing influenza in healthy adults and at least as effective in children.

“I think we’re coming to the realisation that the vaccine isn’t quite as good as we might have initially thought,” said Professor Allen Cheng, an infectious diseases physician at Monash University and one of the authors.

While initial studies were done on healthy individuals, more recent research suggests the vaccine also be not as effective in groups such as the sick and elderly, Professor Cheng said.

“It really depends on if you take a glass half full or glass half empty perspective,” he said. “Fifty percent is better than nothing, and I continue to vaccinate all my patients that are at risk of it.”

While the vaccine should continue to be offered to patients, more investment needed to be made into developing a more effective vaccine, he said.

In particular, Professor Cheng said that high-risk groups other than the elderly were still being under-vaccinated in Australia, including patients with diabetes, heart disease and respiratory illness.

“For example, children with asthma would probably would benefit from the flu vaccine, but very few of them actually are vaccinated,” Professor Cheng said.

However, GP Chris Del Mar, while critical of the observational study, said overall there was very poor evidence that influenza vaccine meaningfully reduced the rate of illness, including in healthcare workers, he said.

Large randomised control trials were needed, said Professor Del Mar, professor of public health at Bond University.

“If there are any benefits they’re small, we’re talking about a number needed to vaccinate of around 1 in 100.”

“I’m really bothered by a more general trend, which is to say that it’s too difficult to do trials because it is too expensive and it may not be ethical, so therefore we’ll do these observational studies and hope that does the job.”

Instead, the recommendation that everyone get the influenza vaccine opened people up to harms that the scientific community was not fully aware of.

“We suspect that the number of febrile convulsions might be really quite high – perhaps nearly as high as 1 in 100 kids who are vaccinated,” he said.

But Professor Paul Van Buynder, Influenza Specialist Group director and public health physician on the Gold Coast, strongly disagreed.

Influenza was a “nasty virus” often underestimated by the community and healthcare practitioners, and was responsible for around 10-15 deaths in children each year, Professor Van Buynder noted.

“Perfect is the enemy of the good,” Professor Van Buynder said. “If the evidence is that the influenza vaccine works in 50-60% of cases, well I know how often no vaccination works – zero.”